Royal Enfield — rusted fuel tank

Address:

Kottayam, Kerala, 686507

I am having royal enfield classic 350 black nd i am having rust in the second tank i changed from the showroom after the 17000km and the first one i changed was due to this rusting problem.. No one is telling a solution for this and due to this rust the vacum piston is getting damaged day by day and getting more and more repairs. Middle class people like us cant afford the tank price and if this is the condition we have to change tank every year